Conventionally, while rod antennas have been widely used as antennas for transmitting and receiving radio waves of car telephones and portable telephones and receiving television broadcast waves, since the construction of these rod antennas requires them to protrude from the vehicle body, there have been caused drawbacks that the protrusion of the antennas is not preferable from safety and aesthetic appearance aspects and that the protruding antenna constitutes a disturbance and may be broken when washing a vehicle.
Due to this, in recent years, there have been demands for antennas with no protrusion such as glass antennas in which an antenna pattern is directly printed on a window glass of a vehicle and antennas in which a seal or sheet on which an antenna pattern is printed is affixed to a window glass of a vehicle, and those antennas have now been put to practical use.
Some of such glass antennas and seal antennas which are now in practical use as car and portable telephone antennas have practically the same transmission and reception gain performance as that of rod antennas.
For example, JP-A-06-152216 discloses a glass antenna for car telephones which is characterized by the inclusion of a radiation pattern whose length in a vertical direction on the surface of a window glass is approximately ¼ of the wavelength and a ground pattern whose length in a horizontal direction on the surface of the window glass is approximately ¼ of the wavelength, wherein the ground pattern is provided on at least one of left and right ends of the window glass surface in such a manner that when the ground pattern is provided on the left end, the radiation pattern is provided so as to be close to a left-hand side portion of the ground pattern, whereas when the ground pattern is provided on the right end, the radiation pattern is provided so as to be close to a right-hand side portion of the ground pattern, so that the ground pattern is formed into a ring-like shape (Patent Document No. 1).
In addition, JP-A-06-314921 discloses a glass antenna provided on a vehicular window glass which is characterized by the inclusion of at least a first element in which a horizontal line is connected to a distal end of a vertical line and a second element in which a horizontal line connected to a distal end of a vertical line and another horizontal line are provided so as to be close to each other vertically in such a manner as to hold the horizontal line of the first element therebetween, so that an end portion of the first element is encompassed by the two horizontal lines (Patent Document No. 2).
Furthermore, JP-A-08-148921 discloses a glass antenna system for car telephones formed by using a conductor pattern on a vehicle window glass which is characterized by being made up of a circular radiation pattern and a doughnut-like shaped ground pattern provided concentrically on an outside of the radiation pattern (Patent Document No. 3).
On the other hand, glass antennas which are now in practical use as vehicular glass antennas for reception of television broadcast waves have practically the same reception performance and gain as those of rod antennas and are disclosed.
For example, JP-A-07-263934 discloses a vehicular glass antenna provided on an upper unused portion on a vehicular rear window glass in which a defogging heater line is embedded which is characterized by the inclusion of a first antenna made up of a horizontal line and a vertical line and a second antenna provided in an unused portion of the first antenna in a left half or right half of the rear window glass in which a line is provided to extend perpendicularly from part of a main element mainly made up of a horizontal line, a transversely elongated rectangular element is connected to the perpendicularly extending line, and a line is drawn out of part of a short side of the rectangular element for implementing a feeding at the side portion of the element (Patent Document No. 4).
In addition, JP-A-2001-119223 discloses a glass antenna provided on a vehicular side window for preferably receiving, in particular, TV radio waves of all bands (Patent Document No. 5).
Furthermore, JP-A-2001-332923 discloses a film antenna in which a rectangular flat plate-like film antenna element is provided on a glass supported by a conductive frame unit for preferably receiving TV radio waves of all bands (Patent Document No. 6).    (Patent Document No. 1) JP-A-06-152216    (Patent Document No. 2) JP-A-06-314921    (Patent Document No. 3) JP-A-08-148921    (Patent Document No. 4) JP-A-07-263934    (Patent Document No. 5) JP-A-2001-119223    (Patent Document No. 6) JP-A-2001-332923
However, since the antenna performance of any of the car telephone or portable telephone glass antennas shown in Patent Document No 1 to Patent Document No. 3 and the TV broadcast waves reception glass antennas shown in Patent Document No. 4 to Patent document No. 6 is liable to be affected by locations where the antenna is placed or structures in the vicinity of the antenna so placed, antenna elements and antenna setting positions must be adjusted vehicle by vehicle. Further, even in case such adjustments are carried out accordingly, the antenna performance has still been changed by the effect of human bodies.
In addition, the car telephone or portable telephone glass antennas shown in Patent Document No. 1 to Patent Document No. 6 have low gains compared with the rod antennas, and hence a further improvement in antenna gain has been desired. Furthermore, as to the TV broadcast waves reception glass antennas shown in Patent Document No. 4 to Patent Document No. 6, not only does a grounding need to be provided in the vicinity of an antenna feeding point but also antenna setting conditions are limited with respect to reception frequencies. In particular, the antenna has to be provided limitedly on the rear window of the vehicle in Patent Document No. 4, on a side window of the vehicle in Patent Document No. 5 and on a large window or door of a structure such as a building in Patent Document No. 6.
In particular, as to the TV broadcast waves reception antennas shown in Patent Document No. 4 to Patent Document No. 5, it was difficult to match the impedance of the antenna to the impedance of the receiver over all the bands of TV broadcast waves to be received.
The invention was made in view of the problems, and an object thereof is to provide a vehicular antenna which can make it difficult for the antenna performance thereof to be affected by antenna setting locations and human bodies so as to reduce an actual antenna area while increasing the antenna performance higher than that provided by the conventional techniques and is hence preferable as a car telephone and portable telephone antenna, as well as a digital broadcast waves and TV broadcast waves reception antenna, which can, furthermore, transmit and receive radio waves of personal radio communication equipment, commercial radio communication equipment and PHS, and which can, moreover, be made difficult to be bound by a position on the surface of a window glass where the antenna is provided.